A standard electrical outlet has open slots that expose children to potentially lethal electrical shock hazards. A curious child is prone to insert a conductive object into one of the slots. A child can be shocked if they are in simultaneous contact with a xe2x80x9chotxe2x80x9d conductor and a low impedance path to ground. To avoid this risk, parents of young children frequently insert nonconductive plugs into all unused outlets to block out other objects. These plugs, however, significantly reduce outlet convenience. Standard AC plugs also create a shock hazard due to their tendency to pull partially out of an outlet, leaving exposed prongs that remain connected to electrical power. A child can easily touch these with their small fingers or a conductive object. Further, in research, industrial or military environments, an explosion hazard exists when electrical outlets are used in the vicinity of volatile chemicals and gases, which can be ignited with an inadvertent spark at an exposed contact.
A safety electrical connection system according to the present invention provides a covered outlet and a corresponding locking plug. Spring-loaded covers block small children from probing the outlet with fingers and foreign objects, yet allow adults to insert a corresponding locking plug without cover removal. Internally, outlet receptacles have no exposed contacts, further reducing the potential for electrical shock. The covered outlet is compatible with existing electrical boxes. A corresponding face plate provides aesthetic wall trim for the outlet and functions to environmentally seal the conductors within. The locking plug is configured to compress the covers when inserted into the outlet. The plug has retracting contacts that extend within the outlet to make a fully-enclosed electrical connection and to lock the plug in place. The plug can be pre-wired as a locking plug or configured as an adapter plug that converts a conventional AC plug to a locking plug.
One aspect of the present invention is a safety electrical connection system having an outlet housing with a front face and a receptacle. The receptacle has an entrance at the front face and access apertures within the receptacle. A nonconductive face plate has an cutout and is mountable to the outlet housing front face so that the cutout aligns with the outlet entrance. Contacts are mounted to the outlet housing near the access apertures and outside the receptacle. The contacts are configured to provide an electrical connection between an external power source and an electrical load. A cover is mounted within the receptacle, the cover is generally urged toward the entrance so as to provide a barrier between the entrance and the access apertures.
In one embodiment, the face plate has a raised wall around the cutout. A shelf inside the receptacle mates with the raised wall when the face plate is mounted to the housing so that the wall becomes a continuous portion of the receptacle. In another embodiment, a plug has a probe that inserts into the receptacle. Prongs retract and extend from the probe. When extended, the prongs electrically connect with the outlet contacts through the aperture. In a particular embodiment, the receptacle, the face plate cutouts and the probe are all keyed. The keying may be a generally triangular shape with rounded corners and a square apex. In another embodiment, the distance from the face plate cutout to the access apertures is at least about 0.6 inches. In yet another embodiment, the outlet housing is installed within a wall-mounted electrical box so that the access apertures are located behind a wall surface.
Another aspect of the present invention is a safety electrical connection system comprising a housing having a generally planar front face and a socket configured to accept an electrical plug. A probe extends from the front face and is configured to insert into an electrical power outlet. Prongs within the probe have an unlocked position retracted into the probe and a locked position extended from the probe. The prongs are adapted to hold the probe inside the outlet in the locked position. A contact is mounted to each prong and is adapted to provide an electrical connection between the power outlet and the socket.
In one embodiment, a finger hold actuates the prongs. The finger hold has a pulled-out position away from the housing and a pushed-in position integrated with the housing. The pulled-out position corresponds to the unlocked prong position and the pushed-in position corresponds to the locked prong position. In another embodiment, the power outlet has a covered receptacle configured to accept the probe, outlet contacts adapted to electrically connect to a power source, and access apertures located between the receptacle and the outlet contacts. The prongs extend through the apertures in the locked position so as to connect the prong contacts with the outlet contacts. In yet another embodiment, the prongs extend generally perpendicularly near the end of the probe. In a particular embodiment, the probe extends at least about 0.6 inches from the housing front face to the probe end. In a further embodiment, the front face has a gasket around the probe so as to provide a seal between the probe and the outlet. In yet another embodiment, the probe and the receptacle are keyed with a generally triangular shape having rounded corners and a square apex.
A further aspect of the present invention is a safety electrical connection method including the steps of installing a receptacle within a building wall so that the receptacle extends from an opening near the wall surface to a bottom interior to the wall and creating an aperture inside the receptacle near the bottom. Other steps are locating a contact interior to the wall, exterior to the receptacle and near to the aperture and routing a source of electrical power to the contact. A further step is accessing the contact through the opening and the aperture so as to provide power to an electrical load. In one embodiment, another step is inserting a spring loaded cover within the receptacle so as to block the opening. In one embodiment, the accessing step involves pushing the cover to the receptacle bottom so as to expose the aperture. In another embodiment, the accessing step comprises the substeps of inserting a probe into the receptacle and extending a prong from the probe through the aperture so as to electrically connect the prong with the contact. In yet another embodiment, the accessing step comprises locking the probe within the receptacle. In a further embodiment, the accessing step comprises the further substep of adapting a standard electrical plug to the probe.